Mammalian somatostatin, a tetradecapeptide, inhibits the release of growth hormone from the pituitary gland. It further inhibits the release of insulin and glucagon from the pancreatic islet cells, inhibits secretion of gastric enzymes and inhibits immune function. Somatostatin agonists and antagonists are continually being sought to aid in the elucidation of the function of the hormone in controlling multiple physiological effects. In particular, a pure somatostatin antagonist, a compound which would successfully compete with the hormone at its receptor site, is of great interest. This compound could be used to block the inhibitory effects of somatostatin, which, in turn, would increase the release of growth hormone, insulin, glucagon and gastric enzymes and would enhance immune function. Although compounds have been discovered which demonstrate partial somatostatin antagonist activity, i.e., some agonist effect, some antagonist effect, pure somatostatin antagonists are still being sought.
Therefore, it is an object of this invention to provide a peptide having pure somatostatin antagonist activity.
It is another object of this invention to provide a method for decreasing the effect of somatostatin.
It is a further object of this invention to provide methods for increasing the release of growth hormone, insulin, glucagon and gastric enzymes in mammals and for enhancing growth and immune function in mammals.
It is a feature of this invention that the growth enhancement of meat producing animals may be effectively and readily obtained. It is an advantage of this invention that the peptide having pure somatostatin antagonist activity also demonstrates inverse agonist activity, i.e. blocks constitutive signalling by somatostatin receptors. Other features and advantages of the present invention will become apparent in the detailed description set forth below.